My PSP can't read my memory stick

Well one day I was just playing a game in my PSP then it suddenly hanged up so what I did is to remove my battery since It won't go off by holding the power button. So I turned my PSP on and now It turns on but can't access the XMB (the memory stick led or whatever you call that thing that flashes if your PSP is accessing your MMS) Is flashing continuosly. But if I removed my MMS, my PSP turns on fine. When I put my MMS back to my PSP, the MMS led then again flashes just like the situation above. Anyone has a solution to that problem?

I don't have one. But I have been thinking, is the problem on the MMS? Do I have to buy a new one? I have to confirm first, because I am already planning to buy a 16GB MMS and I don't want that money to be put to waste.